The Microsoft Exchange 2010 Mailbox Server Role Requirements Calculator is a free, downloadable tool from Microsoft that helps Exchange 2010 administrators design their mailbox server role so that it is optimized for their specific deployment.
The Exchange 2010 Mailbox Server Role Requirements Calculator is comprised of eight different worksheets. Each worksheet focuses on a different part of an Exchange deployment; this includes role requirements, backup requirements, storage, activation scenarios and more. Administrators must fill out each section, of each worksheet, with all of the relevant information that is required in regards to their desired mailbox server role's design. After all information is logged within the various worksheets, the tool calculates exactly what the administrator must do to achieve his intended design.